A breathalyzer or breathalyser (a portmanteau of breath and analyzer/analyser) is a device for estimating blood alcohol content (BAC) from a breath sample. Breathalyzer is the brand name of a series of models made by one manufacturer of breath alcohol testing instruments (originally Smith and Wesson, later sold to National Draeger), and is a registered trademark for such instruments. In Canada, a preliminary non-evidentiary screening device can be approved by Parliament as an approved screening device, and an evidentiary breath instrument can be similarly designated as an approved instrument. The U.S. National Highway Traffic Safety Administration maintains a Conforming Products List of breath alcohol devices approved for evidentiary use, as well as for preliminary screening use.
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